1. Technical Field
The present invention relates to a ball joint for connection between a steerable vehicle wheel and a rack of a rack and pinion steering gear.
2. Description of the Prior Art
A vehicle rack and pinion steering gear includes a rack that is movable axially to effect steering movement of steerable wheels of the vehicle. The movement of the rack is transmitted through steering linkage to the steerable wheels. The steering linkage typically includes a pair of ball joints on opposite ends of the rack. Each ball joint includes a ball stud in a socket. One or more bearings are interposed between the ball stud and the socket. During the life of the vehicle, the parts of the ball joint inevitably wear, producing lash in the ball joint. Excessive lash is undesirable.
The rack and pinion steering gear is typically mounted to the vehicle frame by resilient bushings. The bushings enable a small amount of movement of the steering gear relative to the frame. This movement helps to take up road shocks transmitted from the steerable wheels back through the linkage to the steering gear. This movement can also produce vagueness or other undesirable characteristics in the steering system.
The present invention is an apparatus for connection between a rack of a rack and pinion steering gear and a steerable vehicle wheel. The apparatus comprises a socket including a housing and a stem portion extending in a first direction from the housing. The stem portion is connectable with the rack. The housing defines a chamber and has an opening in communication with the chamber.
A ball stud has a ball portion in the chamber and a stud portion extending from the ball portion through the opening. The ball portion has a center and the stud portion has an axis intersecting the center. The stud portion extends from the ball portion in a direction opposite the first direction. The ball portion of the ball stud has an equator extending perpendicular to the axis of the stud portion, the equator dividing the ball portion into first and second hemispheres.
The apparatus comprises first and second bearings located in the chamber and engaging the first and second hemispheres, respectively, of the ball portion. The apparatus also comprises first and second dampers acting between the socket and the respective first and second bearings and biasing the first and second bearings toward the equator and providing first and second clearances, respectively, between the socket and the first and second bearings.